1. Used as combining form of L. ferrum iron, chiefly Min. in the names of species containing iron, as ferro-calcite, a variety of calcite that contains carbonate of iron and turns brown on exposure (Dana, 1868); ferro-cobaltine, ferro-cobaltite, compounds of iron and cobalt; † ferro-columbite, a synonym of tantalite, columbic and tantalic acid being mistaken for each other (Shepard, 1841); ferromagnetic a., ferromagnetism, ferromanganese, see quots.; ferrotellurite, a tellurite of iron formed as microscopic yellow crystals on quartz; ferro-tungsten, iron containing a certain percentage of tungsten.
1868. Dana, Min., 678. Ferrocalcite. Ibid., 72. Ferrocobaltite.
1844. C. U. Shepard, Min., 154. Ferrocolumbite.
1872–5. Clifford, Lect. (1879), I. 241. Faraday gives reasons for believing that all bodies are either ferromagnetic or diamagnetic.
1881. Maxwell, Electr. & Magn., II. 46. When the magnetization is in the same direction as the magnetic force, as in iron, nickel, cobalt, &c., the substance is called Paramagnetic, Ferromagnetic, or more simply Magnetic.
1850. W. Gregory, Lett. Anim. Magnet., Pref. 15. Heat, light, electricity, and ferro-magnetism. Ibid., Pref. 16. I understand by Ferro-magnetism almost the same as Dr. Faraday does by Para-magnetism; and I use the term in contradistinction to Vital or Animal Magnetism.
1881. Encycl. Brit. (ed. 9), XIII. 352/1, ‘Iron.’ The richer manganeisens (containing 15 per cent. and upward of manganese) used for crucible steels were themselves prepared in crucibles, the term ‘ferro-manganese’ being applied to these products.
1877. Amer. Jrnl. Sc., Ser. III. XIV. 424. Ferrotellurite. A crystalline coating on quartz, associated with native tellurium.
1881. Encycl. Brit. (ed. 9), XIII. 352/1, ‘Iron.’ Biermann of Hanover has prepared ferro-tungsten containing from 20 to 50 per cent. of tungsten and a few parts per cent. of manganese.
2. Chem. Originally used with the general sense ‘containing iron’; but now applied to designate ‘ferrous’ as opposed to ‘ferric’ compounds of iron: cf. FERRI-. † Ferrocyanate = Ferrocyanide (the distinction in quot. 1810–26 belongs to an obsolete theory of the structure of acids and salts). Ferrocyanhydric or ferrocyanic acid, a tetrabasic acid, H4FeCy2, forming a white crystalline powder. Ferrocyanide, a salt of ferrocyanhydric acid, as potassium ferrocyanide, popularly yellow prussiate of potash. Ferrocyanogen, the hypothetical radical FeCy2 supposed to exist in ferrocyanides. † Ferroprussiate = Ferrocyanide. † Ferroprussic acid = Ferrocyanhydric acid.
1810–26. Henry, Elem. Chem. (1826), I. 461. The salt called triple prussiate (ferro-cyanate) of baryta.
1819. Children, Chem. Anal., 327. Ferrocyanic Acid: we are indebted to Mr. Porrett for the first correct ideas of this acid.
1810–26. Henry, Elem. Chem. (1826), I. 463. The compound obtained is, therefore, no longer a prussiate or ferro-cyanate, but a ferro-cyanide.
1842. Grove, Corr. Phys. Forces (1874), 76. This is washed with an acid, which then gives, with ferrocyanide of potassium, the Prussian-blue precipitate.
1869. Roscoe, Elem. Chem., 377. By acting with potassium amalgam on an aqueous solution the ferricyanide is converted into ferrocyanide.
1850. Daubeny, Atom. Th., vii. (ed. 2), 215. Cy 1 + iron 1 forms ferrocyanogen.
1876. Meldola, in Encycl. Brit., V. 555/1, ‘Chemistry.’ The group FeCy6 is regarded as an acid radicle (ferrocyanogen), and a large number of its salts (ferrocyanides) are known.
